Stock-based Compensation - Expense (Details) - USD ($)	3 Months Ended	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2016
Stock-based compensation expense
Stock-based compensation expense	$ 7,352,918	$ 7,352,918
Research and development
Stock-based compensation expense
Stock-based compensation expense	5,260,370	5,260,370
General and administrative
Stock-based compensation expense
Stock-based compensation expense	2,092,548	2,092,548
Stock options
Stock-based compensation expense
Stock-based compensation expense	1,346,761	1,346,761
Restricted stock
Stock-based compensation expense
Stock-based compensation expense	595,317	595,317
Change in control bonus plan
Stock-based compensation expense
Stock-based compensation expense	$ 5,410,840	$ 5,410,840